P0121 — TPS/APP Sensor 'A' Range/Performance
Understanding and troubleshooting the P0121 code
Run a shop or repair van?
Run your next p0121 diagnosis — tps/app sensor 'a' range/performance job in Repairius: estimate, text approval, invoice, paid. Unlimited users.
Start free trial14-day free trial · credit card required · cancel anytime
Fleet, dispatcher or driver?
DispatchTool keeps loads, drivers and breakdowns organized. A separate product from Repairius.
Try DispatchToolQuick answer
- What it means: The Powertrain Control Module (PCM) has detected an issue with the voltage output range or performance of the Throttle Position Sensor (TPS) or Accelerator Pedal Position (APP) Sensor "A."
- Severity: Get it checked soon, but it's often safe to drive home or to a repair shop.
- Most common cause: A faulty Throttle Position Sensor (TPS).
What the P0121 code means
The official OBD-II definition for P0121 is "Throttle/Pedal Position Sensor/Switch
Related P-series codes
P0010
'A' Camshaft Position Actuator Circuit (Bank 1)
P0011
'A' Camshaft Position - Timing Over-Advanced (Bank 1)
P0014
'B' Camshaft Position - Timing Over-Advanced (Bank 1)
P0016
Crankshaft/Camshaft Position Correlation (Bank 1 Sensor A)
P0017
Crankshaft/Camshaft Position Correlation (Bank 1 Sensor B)
P0020
'A' Camshaft Position Actuator Circuit (Bank 2)
P0030
HO2S Heater Control Circuit (Bank 1 Sensor 1)
P0036
HO2S Heater Control Circuit (Bank 1 Sensor 2)
Parts, tools, and pros for this code
Parts pros use for this job
- •Oxygen sensor
- •Spark plugs
- •MAF sensor
Tools pros use
- •OBD-II scanner
- •Code reader
- •Smoke leak tester
Doing it yourself? Shop our partners
We may earn a small commission from partner links — it never changes the price you pay.